Display technology being utilized for digital advertising is not a new concept — Times Square, downtown Tokyo, and other big-city environments typically come to mind when we think of outdoor displays. However, display technology is increasingly finding its way into the great outdoors in new and different formats. While indoor applications still represent about 80 percent of the display market, the pace of growth for outdoor technologies and applications is picking up, thereby expanding manufacturers’ market opportunities.
Outdoor signs have typically been static and made of paper, plastic, or metal. In the last few years, however, electronic signage has become fairly common. Outdoor electronic signs started as cathode ray tubes (CRTs), which served a purpose but posed multiple challenges — they were a couple of feet thick and very heavy, creating the need for a robust, concrete-and-steel mechanical support structure; shielding them from the sun was difficult; and they were not innately attractive. Once liquid crystal displays (LCDs) arrived in the scene, they were viewed as a better alternative. However, they were still several inches thick due to the powerful backlight they required, particularly in an outdoor setting.
Currently, light-emitting diodes (LEDs) dominate the roughly $15 billion outdoor signage market, with LCDs holding a tiny market share in second place. However, electronic paper, or ePaper, is starting to gain ground, with good reason; we'll return to consider this technology shortly.
Using displays in outdoor environments creates challenges, particularly in the daytime. People tend to be outdoors during the day more than at night, and this creates a problem when the sun shines directly on the display — images fade due to poor contrast, and it can be difficult for the viewer to see messages clearly from any angle. Since these displays are essentially competing with the sun, they need to put out a great deal of light to compensate, thereby causing power consumption to go through the roof. Even when used in sports stadiums, shopping malls, and other venues that receive indirect sunlight, they require dedicated high-power cabling and power supplies. Forget about battery backup in case of power loss from the grid. Typically, the cost of power consumption for these large LED signs is paid for by advertisers, by arena owners (actually, by fans via higher ticket prices), or by taxpayers when on public roadways. (Of course, gambling revenues help offset LED power costs in places like Las Vegas.) The recurring costs due to power consumption for large signage displays are non-trivial, but the unit cost of power from the grid (11 cents per kilowatt hour (kWh) is affordable for most operators.
LEDs can stand extremes of weather, whereas LCDs have complicated temperature maintenance requirements. LCD-based signage units contain heaters to warm them when it gets too cold and to keep them at the proper material level (i.e., not too liquid or too crystallized). Hot weather creates further problems; while fans can be inserted, they require a separate outlet, and dust will enter the unit when the fans are not running, clogging up the filters. And fans are not always permissible in some sites, e.g., retail gas stations, where you don’t want to circulate gasoline fumes onto hot surfaces inside the display. Some places, such as train stations, are using LCDs, but they require a very powerful backlight to combat the sun. Making the display visible in sunlight requires a huge amount of power, which — in turn — creates heat and thickness issues, shortens product life, and boosts costs. The bottom line is that cost and power consumption create serious issues regarding long-term outdoor use of LCDs.
How do we solve this power problem? Power consumption by indoor TV displays is problematic, let alone when the display size increases and additional issues associated with outdoor use come into play. The long-term answer to the outdoor-display challenge is reflective or transflective display technologies. The combination of ePaper with specialized LCDs, which can use the sun rather than fight it, is beginning to gain traction. In some applications, such a combination uses 99 percent less power than LED or outdoor LCD, and eliminates glare issues in daylight. For nighttime use, a front light can be set up to reflect off the display to ensure readability is maintained.
ePaper is being employed globally in a growing range of locations, as the accompanying images illustrate. Increasingly, these locations are standalone and remote. In London, for example, ePaper displays are being deployed using a solar cell on top of the sign, which therefore requires virtually no electricity and, when outfitted with WiFi, no data cables.
London bus stop using ePaper (Source: Visionect)
ePaper billboards used in the Slovenian capital of Ljubljana (Source: Visionect)
At the The Society for Information Display (SID) , we believe ePaper for outdoor displays will take off in a major way for a broad range of applications in the next two to three years. For a start, ePaper can be used for street signs — it's visible in areas where inclement weather is an issue, and the display — like any electronic sign — provides a significant leg up as compared to static plastic or paper signs. This can be particularly valuable when a natural disaster occurs. When Fukushima, Japan, was hit by a massive earthquake and tsunami in 2011, for example, large signage displays jointly developed by E-Ink and Toppan were able to keep running in certain cities, consuming just 1% of the power needed by other, similar-sized signs. These very low-power, easily viewed displays became a valuable resource for residents, who would trek to the city center to view updated information on emergency contacts, disaster relief, water quality, and other important news.
One technology that's not being used much for outdoor applications is organic LED (OLED). OLEDs can be viewable outdoors, but — once again — their power consumption is very high, so their cost and lifetime outlook is negatively impacted when used outdoors. However, one specific application for OLEDs is emerging — transparent displays in semi-outdoor applications. Retail shop windows can be replaced with transparent displays, heightening the window shopping experience while providing information that transcends the traditional “card in the window.” Signage providers have begun to offer transparent OLEDs designed to showcase dynamic or interactive information on a transparent glass surface. This can be particularly useful for high-end retail goods, allowing the entire window to offer a means of comparing and promoting products.
Outdoor displays will be showcased during Display Week 2017, which comes to Los Angeles May 21-26. Display Week allows attendees to preview display technologies that they’ll be able to buy in the next few years– not only through demonstrations provided by exhibitors, but also via many high-value workshops and talks. This year’s technical symposium will feature a track on Digital Signage Display Solutions, looking at new and enabling innovations and applications. If this sounds like something you’d like to check out, please register now at DisplayWeek.org, and plan to join us in sunny Los Angeles this spring.
With more than two decades of experience in the technology industry, Sri Peruvemba is the Chief Executive Officer at Marketer International. As the go-to expert source on electronic displays, touch screens, and related technologies for many of the leading technology writers in the country, Sri is frequently quoted in the Wall Street Journal, New York Times, Forbes, Bloomberg, Financial Times, and many other publications. He is also regularly invited to present at major technology conferences, has published several articles and white papers, and often leads seminars and classes on the display industry.
Sri's 25 years of experience in the electronics industry include marketing LCD, CRT, TFEL, OLED, LED, Plasma, and ePaper displays into the mobile, industrial, medical, signage and TV markets. He earned a BSEE, an MBA, and a Post Graduate Diploma in Management. Previously, Sri held senior level positions at E Ink, Sharp Corp, TFS Inc, Planar Systems and Suntronic Technology. He also volunteers his time as Head of Marketing for The Society for Information Display (SID) and also serves as advisor to several technology companies in Europe, Asia, and North America.